The MAGIC Tether Experiment April 22, 2023
University of ColoradoFriday, April 02, 2004
The MAGIC Tether Experiment
A Demonstration of DINO’s MAGIC Boom
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The MAGIC Tether Experiment April 22, 2023
The MAGIC Tether Experiment
• Special Thanks To the KC-135 Team for All of Their Hard Work and Great Contributions– Cook, Evan – Martinez, Mike– McArthur, Grayson – Mohler, Andrew – Parker, Jeff– Seibert, Mike– Stamps, Josh – Worster, Kate
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The MAGIC Tether Experiment April 22, 2023
Background – DINO
• Nadir Pointing– Gravity Gradient Stabilization
• Deployable Boom– Primary Satellite
» 25 kg– Tip Mass
» 5 Kg– MAGIC Tether
» Mechanically-Actuated Gravity-Induced Control
» Stanley Tape Measure» 6m Long
– Lightband» 2 +/- .5 ft/sec» Full deployment after 10 sec
Tip Mass
Tether
DINO
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The MAGIC Tether Experiment April 22, 2023
Why do This Test
• Is this System Even Feasible?– Dynamics of the Semi-Rigid System are Poorly
Understood– Experimental Results of Energy Dissipation
• Over damping will result in inadequate deployment– Poor gravity gradient stabilization
» Science objectives» ADCS power Draw
• Under damping would shock the system– Could damage Electronics and Cameras– Could recoil, causing a collision
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The MAGIC Tether Experiment April 22, 2023
Expected Results
• The MAGIC Tether team expects the following things:– Four standard springs will accelerate the relative velocity of the
tip mass with respect to the primary satellite to approximately 1.7 ft/s (0.518 m/s).
– The tip-off rate of the deployment to be less than 1°/s in each axis.
– Given a deployment velocity of 1.7 ft/s, the optimal value of x0 to be approximately 0.66” to critically damp the system’s motion as the tether is fully deployed.
– The semi-rigid tape to be deployed in a controlled fashion without any recoil at the end of its deployment.
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The MAGIC Tether Experiment April 22, 2023
Experiment Objectives
1. To measure the large-scale and small-scale dynamics in the deployment
• Linear and angular accelerations
2. To empirically measure how the energy in the system can be dissipated
• Spring force in the slow-down mechanism• Critically damp tip mass’ motion
3. To demonstrate a successful deployment of DINO’s MAGIC Boom
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The MAGIC Tether Experiment April 22, 2023
• KC-135• Heavy Sat
– 14.6 kg (32.2 lbs)• Light Sat
– 8.1 kg (17.8 lbs)• Tether
– Two lengths of Stanley Tape Measure (1.0 in)
– 4 ft (1.22 m)• Sensors
– 6 Accelerometers– 6 Rate Gyros
• Equipment Containment System
Overview of the Experiment
Safety Straps
Light Sat
Heavy SatTether
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The MAGIC Tether Experiment April 22, 2023
Structure
• The structure on each of the two satellites (Heavy and Light Sat ) is composed of two 1/8” 6061Al plates connected by 4”-tall 1/4" 6061Al box walls.
• All sharp edges will be covered with pipe insulation
Damping System
Foam Padding
TAZ
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The MAGIC Tether Experiment April 22, 2023
Heavy Sat
• Circular inner plate • Male mating adapter • TAZ • Deployment springs• Data loggers• Dummy loads• Sensors and batteries
Containment box • Hand holds• Pipe insulation
The Heavy Sat will have an overall mass of approximately 14.6 kg and dimensions of 18” x 18” x 6”.
Data Logger
Data Logger
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The MAGIC Tether Experiment April 22, 2023
Light SatThe Heavy Sat will have an overall mass of approximately 14.6 kg and dimensions of 18” x 18” x 6”.
• Circular inner plate • Female mating adapter • Spring Adapters• Data loggers• Dummy loads• Sensors and batteries
containment box • Hand holds• Pipe insulation• Braking System
Data Logger
Data Logger
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The MAGIC Tether Experiment April 22, 2023
Entire Assembly
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The MAGIC Tether Experiment April 22, 2023
Push off Springs x 4
• Based on Planetary System’s Lightband springs
• K = 22.5 lb/in (Per Spring)• Finitial = 60 lb (Total)
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The MAGIC Tether Experiment April 22, 2023
Tether Description
• The semi rigid tether (SRT) – Two face-to-face Tape Measures– Commercial, off the shelf part
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The MAGIC Tether Experiment April 22, 2023
Tether Mounting
• Deployment / Braking System mounted in Light Sat (Tip Mass)
• Boom mounted to Heavy Sat (Main Satellite) with a tether attachment system (TAZ), designed to maintain the rigid natural shape of the tether, while providing a secure attachment.
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The MAGIC Tether Experiment April 22, 2023
Deployment System
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The MAGIC Tether Experiment April 22, 2023
Damping System• 42 Teeth per Rotation
• 366 Teeth per Full Deployment• 3.1 J Total Energy
• .0085 J / Tooth
• Two 2.5 inch spools
• Geared to counter rotate• Ratchet and Pawl
• Pawl Spring Loaded• Adjustable Initial Compression
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The MAGIC Tether Experiment April 22, 2023
Damping System
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The MAGIC Tether Experiment April 22, 2023
Mechanical Dial
• In Flight Spring Adjustment
• .55in - .75in
• Linear Transducer
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The MAGIC Tether Experiment April 22, 2023
Release System
• Deployment initiation – Mechanical System– Hand held actuating lever
• Bicycle brake– Release cable – Switch
• Incorporated into handle• Initiates data collection
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The MAGIC Tether Experiment April 22, 2023
Testing
DAY 1• Set Spring to maximum
compression, .75in (Over Damped)
• Position Test Equipment• Deploy• Reset• Decompress spring .05in• Repeat until .55in
compression is reached (Under Damped)
DAY 2• Set Spring to maximum
compression in range of interest
• Position Test Equipment• Deploy• Reset• Decompress spring
desired amount• Repeat until minimum
compression in range of interest is reached
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The MAGIC Tether Experiment April 22, 2023
Data Collection
• There will be four sources of data in the MAGIC Tether Experiment: – Qualitative observations by the flyers and by the
digital video camera– Quantitative measurements of acceleration by the six
single-axis accelerometers– Quantitative measurements of angular velocities by
the six single-axis gyroscopes– Quantitative measurements of braking spring
compression by the linear transducer
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The MAGIC Tether Experiment April 22, 2023
Safety
• Restraint Straps– Four cinch straps to hold satellite to base plate during Takeoff/landing– Two Velcro straps for satellite securing during flight– Velcro connection between Heavy Sat and base plate during flight
• Safety straps– 10’ straps connected from the base plate to each satellite– 6’ strap connecting each satellite– Braided steel rated to 1000 lbs.
• Safety pin– Prevent accidental deployment
• Padding on all metal edges• Four handholds per satellite• Safety straps attached to all tools• Fuses installed on electrical lines
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The MAGIC Tether Experiment April 22, 2023
Results
• Trends will be extrapolated and scaled to DINO’s full Deployment length and weight.
• What will happen to the satellite if the damping system does not perform precisely as planned?
• What are the risks to the Satellite?• Does the Tether “explode” violently?• Is the deployment controllable?• Does the damping occur as expected?
• Real world experience• Will result in a safer, more reliable system for DINO
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The MAGIC Tether Experiment April 22, 2023
Appendix
The MAGIC Tether Experiment April 22, 2023
FEA for KC-135 Experiment
Grayson McArthur
Colorado Space Grant Consortium & DINO
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The MAGIC Tether Experiment April 22, 2023
G-Load Specs
Takeoff/landing- Forward 9 g’s- Aft 3 g’s- Down 6 g’s- Lateral 2 g’s- Up 2 g’s
3 g’s in any direction - Randomly picked 3 configurations to simulate the structure being dropped
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The MAGIC Tether Experiment April 22, 2023
FEA Setup
Program used for analysis → CosmosWorksTakeoff/landing- Load acts through the center of gravity- Outer face of the outer panel on the light side restrained as immovable/no translation to simulate attachment to base plate- Global size of nodes set at 0.44469 in. with a tolerance of 0.02223 in.- Yield strength of Al 6061 used as max. load = 145 MPa or 21030.51 psi- Factor of safety set at 2 based on the yield strength
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The MAGIC Tether Experiment April 22, 2023
FEA Setup Con.
3 g’s in any direction - Load acts through the center of gravity- Global size of nodes set at 0.44469 in. with a tolerance of 0.02223 in.- Yield strength of Al 6061 used as max. load = 145 MPa or 21030.51 psi- Factor of safety set at 2 based on the yield strength► Thin edge faces of outer plates set as immovable/no translation to simulate the structure being dropped on those two edges
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The MAGIC Tether Experiment April 22, 2023
Results
Stress: Von Mises (VON)- Measured in pounds per square inch- VON = (0.5[(P1-P2)2+(P1-P3)2+(P2-P3)2])1/2
- P1,P2,P3 are principle stresses- Measures stress intensity required for a material to start yielding
Strain: Equivalent Strain (ESTRN)Displacement: Resultant (URES)- Measured in inches- Adds displacement vectors in X,Y,Z direction to get a resultant vector
Design Check- FOS < 2 area shows as red- FOS > 2 area shows as blue
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The MAGIC Tether Experiment April 22, 2023
Stress
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The MAGIC Tether Experiment April 22, 2023
Strain
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The MAGIC Tether Experiment April 22, 2023
Displacement
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The MAGIC Tether Experiment April 22, 2023
Design Check
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The MAGIC Tether Experiment April 22, 2023
Conclusions
The structure will be able to withstand all the prescribed loads as indicated in NASA document AOD 33897 Experiment Design Requirements and Guidelines NASA 931 KC135AStructure will survive a 3 g impact such as being dropped by the flight crew during transition from 0 g to 2 g
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The MAGIC Tether Experiment April 22, 2023
Issues and Concerns
Mesh resolution was limited due to computer memory and time limitationsBoundary conditions being appropriate for load case
The MAGIC Tether Experiment April 22, 2023
Onboard Support Equipment
Equipment Containment System
(ECS)
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The MAGIC Tether Experiment April 22, 2023
Entire Assembly
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The MAGIC Tether Experiment April 22, 2023
Base Plate
• .125-.25in Al 6061 sheet
• Note, Current design requires heavy hand construction… It will not fit within the CNC
• 4 Aircraft mounting location
• 7 handhold, accommodating up to 4 handlers
• Experiment restraint harness
• Safety cable attachment
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The MAGIC Tether Experiment April 22, 2023
Tool Box
• Store bought
• Plastic and steel construction
• Round plastic edges
• Lockable
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The MAGIC Tether Experiment April 22, 2023
Stand Off
• Al 6061
• Industrial strength Velcro
• Non permanent attachment
• Only for stability, not critical for LD/TO
The MAGIC Tether Experiment April 22, 2023
Mechanisms
Michael Martinez
Colorado Space Grant Consortium & DINO
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The MAGIC Tether Experiment April 22, 2023
Mechanisms
• Contents:– Tether Description– Deployment System– Braking System
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The MAGIC Tether Experiment April 22, 2023
Tether Description
• The semi rigid tether (SRT) is constructed of 2 COTS spring metal "tape measures", four feet length by 1 in wide, curved along their width.
• To be configured ‘face to face’, provides greater stability.
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The MAGIC Tether Experiment April 22, 2023
Deployment System
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The MAGIC Tether Experiment April 22, 2023
Deployment System (cont)
• The MAGIC Tether deployment system consists of two 2.5 inch spools, geared to counter rotate and unwind the spring metal boom in a controlled manner.
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The MAGIC Tether Experiment April 22, 2023
Deployment System (cont)
• Deployment / Braking System
– The stowed SRT will be wound on the two spools such that when deployed the two tape measures will be face to face, forming a rigid structure.
– Tape to spool connection recessed to reduce stress at connection
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The MAGIC Tether Experiment April 22, 2023
Braking System
• Velocity control is provided by a 48 tooth, 2.0 inch ratchet and pawl system, with the ratchet shafted to the geared spool, and the pawl spring loaded to provide a loading / braking force against the ratchet.
• Initial k for spring ~ 0.245 N/mm
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The MAGIC Tether Experiment April 22, 2023
Release System
• Deployment initiation – Mechanical System– Hand held actuating lever
• Bicycle brake– Release cable – Switch
• Incorporated into handle• Initiates data collection
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The MAGIC Tether Experiment April 22, 2023
Tether Reset Device
• Tether reset device• Two options
– Manual crank– Electric drill
• Flexible extension used to reach the drive shaft easily
• Attached to the toolbox by a steel cable tether
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The MAGIC Tether Experiment April 22, 2023
Tether Mounting • Deployment / Braking
System mounted in Light Sat (Tip Mass)
• Boom mounted to Heavy Sat (Main Satellite) with a tether attachment system (TAZ), designed to maintain the rigid natural shape of the tether, while providing a secure attachment.
The MAGIC Tether Experiment April 22, 2023
Sensors
Kate WorsterMichael Seibert
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The MAGIC Tether Experiment April 22, 2023
Sensors: Objectives
• The Sensors Subsystem is designed to measure the large-scale and small-scale dynamics of the experiment during its deployment, including linear and angular accelerations imparted by the tether
• Sensors and Data Acquisition– Onboard storage of science and engineering data– Provide data for post-flight analysis
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The MAGIC Tether Experiment April 22, 2023
Sensors & Data Acquisition System Functional Diagram
Data Signal
Power lines
Data Logger
HVY_AZHVY_AYHVY_AZ HVY_G3HVY_G2HVY_G1
KS
9V15V
Heavy Side
KSKill Switch
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The MAGIC Tether Experiment April 22, 2023
Sensors & Data Acquisition System Functional Diagram
Data Signal
Power lines
Data Logger
LHT_AZLHT_AYLHT_AZ
LHT_G3
LHT_G2
LHT_G1
KS
9V15V
LHT_T_D
Light Side
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The MAGIC Tether Experiment April 22, 2023
Functional Requirements
Requirements Accelerometer Rate Gyro
Linear Transducer
Data Logger
Laptop
Measure acceleration
Measure twist & rotation
Measure spring
compression
Data acquisition &
analysis
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The MAGIC Tether Experiment April 22, 2023
Gyro Specifications-ADXRS150EB
• Surface-mount package of 7mm x 7mm x 3mm and mass of 0.5 grams.
• Each rate gyro has a resolution of 0.05/s/Hz and a dynamic range of 150/s.
• Input voltage of 5.00v DC from onboard power supply and a quiescent supply current between 6.0-8.0 mA.
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The MAGIC Tether Experiment April 22, 2023
Accel. Specifications-ADXL150
• Nominal sensitivity: 38.0mV/g and a maximum sensitivity of 43.0mV/g.• The functional voltage range 4.0V - 6.0V and a quiescent supply current of
1.8mA for nominal operation and 3.0mA as the maximum supply current.• Resolution: 1.0mg/Hz• Dynamic range: 80dB• Each can withstand 2000 g’s when un-powered and 500 g’s when powered
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The MAGIC Tether Experiment April 22, 2023
9V Power Supply Specifications
9V ZnMn2 battery• Average voltage of 9.0 volts • Average capacity of 655mAhr (0.8 volts per cell • Weighs 45.6 grams (1.6oz) and has a total volume of 21.2cm3 (1.3in3).
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The MAGIC Tether Experiment April 22, 2023
15V Power Supply Specifications
1.5V Alkaline Zinc-Manganese Dioxide (ZnMn2) battery• Average voltage of 1.5 volts • Average capacity of 3135mAhr (0.8 volts per cell• Weighs 23.0 grams (0.8 oz) and has a total volume of 8.1cm3 (0.5in3).
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The MAGIC Tether Experiment April 22, 2023
COTS Parts Status
Part Availability StatusADXL150 In stock on Analog
Devices websiteNot yet ordered
ADXRS150 In stock on Analog Devices website
Not yet ordered
Inhibits Available at CSGC and JB Saunders
Have some, others will be purchasing next week
Sensor housing, 18 gauge wire, prototype board
Available at JB Saunders Purchasing next week
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The MAGIC Tether Experiment April 22, 2023
Data Collection
• Omnidata Polycorder and Data Fielder loggers
• 415K on board storage• 25Hz sampling rate• Start/Stop trigger capability• 10 analog input channels• 0V-5V, 0V-10V & 0V-15V
input ranges
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The MAGIC Tether Experiment April 22, 2023
Data Collection
• Heavy Sat– 6 Inputs
• 3 Accelerometers• 3 Rate Gyroscopes
• Light Sat– 7 Inputs
• 3 Accelerometers• 3 Rate Gyros• 1 Linear Transducer
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The MAGIC Tether Experiment April 22, 2023
Data Collection
• Configuration– Omnidata DF200 GUI– RS-232– Variables
• Sampling Rate• Saving Rate• Channel Input Voltage
Range
• Data Retrieval– Omnidata DF200 GUI– RS-232– Data Retrieval Options
• Histogram• Spreadsheet
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The MAGIC Tether Experiment April 22, 2023
Ground Support Equipment Requirements
• Laptop– RS232 Capability
• Serial Port• USB to Serial adapter
• Spring Set Screw Calibration– Calipers
• Initial state displacement measurement
The MAGIC Tether Experiment April 22, 2023
Procedures
Jeff Parker
Colorado Space Grant Consortium & DINO
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The MAGIC Tether Experiment April 22, 2023
In-Flight Procedures• Preparations for the First Parabola• These procedures must be followed to set the experiment up for the first
parabola:1. Flyer B: verify that the digital video camera is on and working normally.2. Flyer A: verify that the sensors’ wiring harness is connected to the first data logger on
each satellite.3. Flyer A: turn on power to both satellites by switching the kill switch into the on
position. Flyer B: verify that power has been turned on. An LED will indicate normal power for each battery system onboard. Flyer B: replace any battery packs that require replacing.
4. Flyer A: configure each of the two data loggers using a brief set of instructions attached clearly to the equipment containment toolbox. Flyer B: verify every instruction as they are entered.
5. Flyer B: verify the setting of the slow-down mechanism.6. Flyer B: remove the four cinch straps from the experiment and stow them in the
equipment containment toolbox. Flyer A: assist as necessary. This leaves two Velcro straps still attached to the experiment system.
7. Flyers A and B: visually inspect the experiment to make sure that everything is in working order, including the Velcro straps, the safety straps, the deployment system, the safety deployment pin, and the slow-down mechanism.
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The MAGIC Tether Experiment April 22, 2023
In-Flight Procedures• Free-Fall minus three minutes8. Flyer A: remove the safety deployment pin and Velcro it to the side of Heavy Sat (it
also has a short tether attached to it to restrain it from possibly floating away).9. Flyer B: check the temperature of the cabin using the thermometer attached to the
toolbox.10. Flyer B: record all settings and activities in the logbook. The ambient temperature, air
currents, and other environmental factors should be noted.• Free-Fall minus one minute11. Flyer A: release one of the two remaining Velcro hold-down straps. If the experiment
behaves in an unexpected manner, immediately replace the straps and inspect the deployment system. This may sacrifice the parabola, but it could avoid releasing an uncontrolled deployment.
12. Flyer B: prepare the active data logger on each satellite. This requires about eight key-strokes that will be easily visible near the data logger on the system.
13. Flyer A: release the last hold-down Velcro strap (the satellite system still has Velcro attached to its base to keep it still on the base plate).
14. Flyers A and B: situate yourselves such that your feet are restrained by the foot-restraints and you are on opposite sides of the flight system. Make sure that Flyer A will be near Heavy Sat and Flyer B will be near Light Sat upon deployment completion.
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The MAGIC Tether Experiment April 22, 2023
In-Flight Procedures• Free-Fall15. Flyers A and B: make sure you are stable in the foot-restraints and prepared for the experiment.16. Flyers A and B: lift the experiment off of the base plate and maneuver into the correct position
over the base plate. During the deployment, the Light Sat will move approximately 2.5 feet and the Heavy Sat will move approximately 1.5 feet. Hence it is important to deploy the system in the proper location in space such that the full deployment occurs within the specified experiment volume. This position is marked on the base plate.
17. Flyer A: hold and stabilize the satellite system from the side such that the deployment action will occur sideways and that Flyer A will be near Heavy Sat and Flyer B will be near Light Sat upon deployment completion.
18. Flyer A: take hold of the deployment trigger.19. Once all personnel are clear from any interference with the MAGIC Tether’s deployment (keeping
in mind that both the primary and tip mass systems will move upon deployment), then Flyer A: carefully release the system and trigger the deployment. Keep hold of the deployment trigger, both as a safety and because letting it go might induce added dynamics into the system.
20. The separation springs activate and the deployment proceeds.21. The tether is reeled out from the Light Sat; accelerometers and rate gyros on both bodies
measure the linear and rotational accelerations experienced by both systems; the data are recorded on the data loggers.
22. The slow-down mechanism removes energy from the moving system from the moment of deployment until the system comes to a stop.
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The MAGIC Tether Experiment April 22, 2023
In-Flight Procedures23. The Light Sat either comes to a halt with respect to the Heavy Sat or it recoils after
the tether stretches taut. Flyer B records the resulting dynamics in the logbook. Flyer B then records the distance that the tether deployed by observing the tic marks on the tether.
24. The maximum separation velocity between the two bodies is 1.7 ft/s, slow enough to grapple if need be. Therefore, if any recoil action exists that appears to threaten a collision between the two satellites, then Flyer A: carefully grapple the two satellites prior to impact. If, however unlikely, the system recoils at an unexpectedly high velocity, then Flyer A: remain in a safe position and wait until the system settles down before retrieving the hardware.
25. If not otherwise retrieved, Flyer A: take hold of the Heavy Sat.26. Flyer B: take hold of the Light Sat. 27. Flyer A: place the Heavy Sat onto the Velcro swath on the base plate to secure it
before the end of the free-fall.• End of Free-Fall28. Flyer B: keep hold of the Light Sat while the aircraft’s accelerations increase.29. Flyer A: use the tether-reset device to recoil the tether onto the spools.30. Flyer B: mate the Light Sat onto the Heavy Sat, compressing the separation
springs. The deployment device will not allow the springs to release until triggered, so there is no danger of accidental deployment during this phase.
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The MAGIC Tether Experiment April 22, 2023
In-Flight Procedures31. Flyer A: strap the system down using the two Velcro hold-down straps.32. Flyer B: command the two active data loggers to stop recording data.33. Flyer B: adjust the knob on the slow-down mechanism to set the slow-down spring to the next
desired value of x0. Flyer A: verify the set value.34. Flyer B: record all dynamics, activities, and new settings in the logbook. The ambient
temperature, air currents, and other environmental factors should be noted.35. Flyers A and B: while waiting for the next free-fall, visually inspect the system for signs of
fatigue, failures, or damage. If power sensors indicate a battery pack low on power, replace the battery pack at this time. If a data logger is nearing memory capacity, then switch the power and data cables from the active data logger to the spare data logger. Follow the startup procedure listed in line 4.
36. Return to step 11 and repeat.• End of Flight37. Flyer A: place the deployment safety pin into the deployment system.38. Flyer A: secure all four additional cinch straps on the system.39. Flyer B: shut the data loggers down following the simple procedures listed on the side of the
structure.40. Flyer B: flip the kill switch on each satellite, turning off power to each system.41. Flyer A and B: verify that all straps are in place and secure.42. Flyer A and B: verify that all components are stowed and secure.
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The MAGIC Tether Experiment April 22, 2023
Emergency Procedures
• In the event of an emergency, the following procedures will be followed. These procedures will be posted directly on the experiment, detailing exactly how to shut the system down quickly.1. If either satellite is not strapped to the base plate, follow the
appropriate procedures here:• Flyer A: take hold of the Heavy Sat• Flyer B: take hold of the Light Sat• Flyer A: place the Heavy Sat on the base plate• Flyer B: mate the Light Sat on the Heavy Sat• Flyer A: strap the system down using the two Velcro straps
2. Switch the master kill switch on each satellite to shut off all power on each satellite.
3. Shut off the power to the data loggers.
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The MAGIC Tether Experiment April 22, 2023
Safety
• Restraint Straps– Four cinch straps to hold satellite to base plate during Takeoff/landing– Two Velcro straps for satellite securing during flight– Velcro connection between Heavy Sat and base plate during flight
• Safety straps– 20’ straps connected from the base plate to each satellite– 6’ strap connecting each satellite– Braided steel rated to 1000 lbs.
• Safety pin– Prevent accidental deployment
• Padding on all metal edges• Four handholds per satellite• Safety straps attached to all tools• Fuses installed on electrical lines
The MAGIC Tether Experiment April 22, 2023
Data Analysis
Jeff Parker
Colorado Space Grant Consortium & DINO
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The MAGIC Tether Experiment April 22, 2023
Data Types
• There will be four sources of data in the MAGIC Tether Experiment: – Qualitative observations by the flyers and by the
digital video camera– Quantitative measurements of acceleration by the six
single-axis accelerometers– Quantitative measurements of angular velocities by
the six single-axis gyroscopes– Quantitative measurements of braking spring
compression by the linear transducer
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The MAGIC Tether Experiment April 22, 2023
Data Reduction
• Accelerometers and rate gyros have biases and scale factors– Calibrated by temperature measurements and
specific calibration measurements• Analog measurements between 0 – 5 Volts• Expected Dynamics:
– Large acceleration spike at beginning of deployment– Diminishing decelerations until end of tether or all
energy is dissipated– Possible dynamics due to tether’s deployment– Possible recoil dynamics due to excessive energy
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The MAGIC Tether Experiment April 22, 2023
Expected Results
• The MAGIC Tether team expects the following things:– Four standard springs will accelerate the relative velocity of the
tip mass with respect to the primary satellite to approximately 1.7 ft/s (0.518 m/s).
– The tip-off rate of the deployment to be less than 1°/s in each axis.
– Given a deployment velocity of 1.7 ft/s, the optimal value of x0 to be approximately 0.66” to critically damp the system’s motion as the tether is fully deployed.
– The semi-rigid tape to be deployed in a controlled fashion without any recoil at the end of its deployment.
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